Plural loudspeaker sound effect system

ABSTRACT

A sound effect system comprising a plurality of loudspeakers adapted to be spaced about a stage or platform on which performers are positioned, or about a listening area, a single source of electrical audio signal for all of said speakers, a photoresistive light cell in the source wire to each of said speakers, a light source directed at all of said cells, and means for interrupting the light to said cells in virtually any predetermined pattern or cycle.

United states Patent [72] inventor David L. Beatty [56] References Cited 2 Adams, h n iomKm. UNITED STATES PATENTS [21] A l N 322 3,272,906 9/1966 De Vries m1. l79/l(.6)X {22] 55 1 1969 3,299,208 l/l967 Driemeyer l79/1(.3PS)

[45] Patented Mar. 9,1971 3,414,873 12/1968 Richard et al. 340/5 Primary Examiner-William C. Cooper Attorney-John A. Hamilton [54] PLURAL LOUDSPEAKER SQUND EFFECT r SYSTEM I ABSTRACT: A sound effect system compnsmg a plurality of 13 claims 9 Drawing Figs loudspeakers adapted to be spaced about a stage or platform [52] U.S. C 179/1, on which performers are positioned, or about a listening area, 179/1-06 a single source of electrical audio signal for all of said [51] Int. H04? 5/04 speakers, a photoresistive light cell in the source wire to each [50] Field ofSearch 179/1 l of said speakers, a light source directed at all of said cells, and

(V18), 1 (A), 1 (VOL), 1.2, 1.6, 1.3 (PS), 1 (AT); 181/5; 250/199, (lnquired), 215

means for interrupting the light to said cells in virtually any predetermined pattern or cycle.

PLURAL LOUDSIER SOUND EFFECT SYSTEM This invention relates to a new and useful improvements in sound systems, and has particular reference to sound systems used by small instrumental music groups, although the invention is not limited to this usage. Such systems customarily include a plurality of loudspeakers fed from one or more microphones and distributed about the stage or platform on which the musicians work, or about the auditorium, dance floor or other listening area in which the audience is positioned. In such systems, the purpose of the multiple speakers is generally to insure efficient and thorough distribution of the sound to all parts of the listening area.

The principal object of the present invention is the provision, in a system generally of the type described above, of novel means whereby the sound, or a major portion of it, emanates at any given moment from one of the speakers, or from any number of speakers less than the total number, then from another speaker or set of speakers, and so on in a continuously repetitive cycle. By properly selecting the number of speakers and controlling the cycle, many novel sound effects may be obtained. For example, the apparent source of the sound, so far as a listener is concerned, may be made to oscillate at any desired speed from one side of the stage or platform to the other side, or may be made to rotate all the way around the audience, as if the performers were on a stage rotating around the audience. By synchronizing the speaker cycle with the tempo of the music, other effects are possible, for exam ple, the heavily accented beat" of the drum and other rhythm instruments of the group may be made to appear to emanate from one source, while themelodic notes between the beats appear to emanate from another source. Generally this object is accomplished by the insertion in the source wire of each speaker of a photocell of the type the electrical resistance of which is varied by the intensity of light impinging thereon, and by the provision of a light source for said cells, and mechanically driven means for interrupting or passing light to said cells according to a prearranged cycle or pattern.

Another object is the provision of a sound effect system of the character described having novel and simple means whereby an infinite number of types and-variation of sound patterns or cycles may be provided. Included are interchangeable interrupters for providing any number of basic patterns or cycles, means for moving the light cells relative to the interrupter to effect phase changes of the individual speakers within these basic patterns, variable-resistance bypasses around the light cells, to vary the proportion of. the speaker outputs controlled by the light cells, means for reversing the effect of the light cells so that a light change previously causing an increase of speaker volume then causes a reduction of volume, means for varying the intensity of the light source, and means for varying the speed and reversing the operation of the interrupter. Also provided is a visual signal synchronized with the interrupter, for use in the event the musicians desire to match the tempo of their music with the cyclical frequency of the speakers, and means for adjusting the phase relationship between the signal and the interrupter.

Other objects are simplicity and economy of construction,

and efficiency and dependability of operation.

With these objects in view, as well as other objects which will appear in the course of the specification, reference will be had to the accompanying drawing, wherein:

FIG. I is a partially schematic and partially structural dia gram of a sound effect system embodying the present invention,

FIG. 2 is a sectional view taken on line ll-ll of FIG. 1,

FIG. 3 is a sectional view taken on line III-Ill of FIG. 1, partially broken away,

FIGS. 4-7 are views similar to FIG. 2, with parts omitted, showing various types of interchangeable interrupter discs,

FIG. 8 is a view similar to FIG. 2, showing an interrupter disc of modified form, and

FIG. 9 is a view similar to FIG. 2, showing still another modified form of interrupter disc.

Like reference numerals apply to similar parts throughout the several views, and the numerals 2, 4 and 6 apply respectively to three loudspeakers of the system. Said speakers may for the purposes of illustration be presumed to be disposed respectively at left, center and right of a stage or other platform from which an instrumental music group performs, and directed toward the audience listening area. It will be apparent, however, that any number of speakers may be included in the system, and arranged in any desired relationship to the listening area. An electrical audio signal isfurnished to the speakers by a source wire 8 from a suitable standard source such as a microphone l0 and a. preamplifier 12. Said source wire is connected to each speaker through a manually variable resistor 14 and an amplifier 16, said resistor and amplifier being connected in series with each other. Resistors 14 may be individually and separately controlled, or if desired may be interlinked by means indicated at 18 to be gangoperated by a single control knob 20.

Bypassing the resistor 14 in the circuit of each speaker, so as to be disposed in parallel relation therewith, is a conductor including, in series from source wire 8, a. wire 22, a photoelectric cell, the cells associated with the three speakers 2, 4 and 6 being designated respectively at 24, 26, and 28, a wire 30, and the armature of a manually operable switch 32 having two fixed contacts 34 and 36 with which the armature may be selectively engaged. The contacts 36 of these switches are each connected directly to the amplifier 16 of the associated speaker, while contacts 34 are grounded at 38. All of switches 32 may be manually controlled; or if desired may be interlinked by means indicated at 40 forgang-operation by a single control knob 42. Photoelectric cells 24, 26 and 28 are preferably of the photoresistive type, the resistance of which to an electric current varies inversely to the intensity of light impinging thereon. That is, the brighter the light impinging thereon, the lower the electrical resistance thereof, and the dimmer the light, the grater the resistance.

Each of photoelectric cells 24, 26 and 28 is mounted in a small, individual housing 44 having a permanent magnet 46 forming the base thereof, whereby said housings are yieldably fixed on, but slidably movable over, the top surface of a fixed horizontal plate 48. Radial guide lines 49 may be imprinted on plate 48 to assist in accurate angular placement of the photocells on the plate. The electrical leads to each cell housing are made by means of a flexible cable 50 so as not to interfere with movement of the cell housingson the plate, and each cell housing is provided with a handle 52. The photoelectric cells are disposed to receive light from above.

A vertical shaft 54 carried rotatably by a fixed bearing 56 extends upwardly through a hole 58 provided therefor in plate 48, and a planar, generally circular interrupter disc designated generally by the numeral 60 is affixed to the upper end of said shaft, said interrupter disc being generally concentric to the shaft and disposed in a plane parallel to plate 48, but at an elevation just above photocells 24, 26 and 28. The interrupter disc is mounted on shaft 54 between a flange 62 of said shaft below said disc, and a knurled clamp nut 64 threaded on said shaft above the disc, whereby said disc is secured tightly to the shaft for rotation therewith, but may be easily and quickly removed for the substitution of other interchangeable discs, as will appear. Disposed above disc 60, in closely spaced relation thereto, is a downwardly directed parabolic reflector 66 having a diameter generally equal to the maximum diameter of the disc, and having mounted at its locus an electric lamp 68 adapted to direct light of generally uniform intensity downwardly over the entire area of a circle established by the maximum area of disc 60. Reflector 66 is stationary during normal use, but is mounted by any suitable means, not shown, for movement away from disc 60 to permit access for changing discs when desired. Lamp 68 is connected operatively to line wires 70 and 72 through a manually variable resistor 74, whereby the intensity of the lamp may be adjusted. Photocells 24, 26 and 2d are all disposed beneath reflector 66 and interrupter disc 60. As will be described, disc 60 may be opaque but with portions thereof cut out, or may be solid but of varying degrees of transparency, so that as it is rotated by shaft 54,- light 'will be allowed to reach the various photocells in various patterns, cycles and sequences.

As shown, shaft 54 is rotated by a small electric motor 76 having a permanent magnet base 78 slidable on a fixed horizontal plate 80 disposed beneath plate 48, the horizontal output shaft 82 of said motor having mounted thereon a friction wheel 84 which is in engagement with a planar driving disc 86 fixed on shaft 54 and disposed in a plane at right angles to said shaft. By sliding magnet 78 to dispose wheel 84 closer to shaft 54, the rotational speed of said shaft is increased, and by sliding the magnet on plate 86 to dispose wheel 84 father from shaft 54, the speed of said shaft is decreased. Motor 76 is connected to line wires 72-74 through a manually variable resistor 88, whereby the motor speed may be changed, and through a suitable reversing switch 90 whereby the direction of rotation of the motor may be reversed. Changing the speed of shaft 54 by moving motor 76 is intended primarily for use in making coarse and relatively permanent adjustments, while changing of the speed of shaft 54 by means of resistor 88 is intended for making relatively fine adjustments, or for adjustments which may be desired to be made with extreme rapidity, such as between successive beats of a musical composition, at a tempo change of the composition.

A flasher lamp 92 is provided, at a position visible to the performers, or to their director, and is operable to flash on momentarily once during each revolution of interrupter disc 60. This is used as a guide for the musicians, in the event it is desired to synchronize the music tempo with the cyclical frequency of speaker operation. As shown, said lamp is operated by a cam 94 fixed on shaft 54 below disc 86 and having a single radially projecting lobe 96 operableat one point in each revolution of shaft 54 to engage the operating member 98 of a normally open electric switch 100, whereby to close said switch momentarily. Lamp 92 is connected to line wires 72 and 74 through switch 100. Said switch is carried in a housing 102 mounted on an arm 104 projecting radially from a hub 106 rotatable on shaft 54. Also fixed on hub 106 is a wonn wheel 108 which may be adjustably turned by means of a worm 110 disposed tangentially to said worm wheel and fixed to an axially extending shaft 112 rotatably carried by a fixed bearing 114 and rotatable by means of knob 116. The purpose of the adjustment provided by turning switch 100 angularly about shaft 54 is to permit adjustment of the phase of lamp 92 with respect to the cycle of the speaker operation provided by one full revolution of interrupter disc 60, so as to flash at any desired point of said cycle.

In operation, assume first that switches 32 are closed on contacts 36, so as to insert the photocells 24, 26 and 28 into the circuits of the respective speakers, and that resistors 14 are set high so that very little if any of the speaker signal from source wire 8 flows therethrough, but must flow, if at all, through the photocells. Assume also that the photocells are arranged on plate 48 at l20 angular intervals under the peripheral'edge portion of interrupter disc 60, and that the interrupter disc is configurated as shown in H0. 2. As will be seen in that view, a portion of the periphery of the disc is cut away to form a portion 118 of smaller diameter and a portion 120 of a larger diameter, so that notch 118 uncovers the photocells and admits light from lamp 68 to impinge thereon in a predetermined sequence and pattern as the disc is rotated by motor 76. The notching of the disc, which is opaque to light, provides a pair of shoulders 122 and 124 which confront each other angularly across notch 118, and which pass directly over the photocells as the disc is rotated. As shown, shoulders 122 and 124 are inclined acutely to the direction of travel of the edge of the disc, so as to cover or uncover each photocell gradually, requiring rotation of the disc through a considerable angular extent to effect either operation. Thus, with the disc rotating in the direction of arrow 126 in FIG. 2, and at the angular position shown, photocell 24 is being gradually uncovered by shoulder 122, the light impinging on said cellgradually decreasing the resistance thereof to increase the volume of speaker 2. At the same time, shoulder 124 is gradually covering cell 28 to decrease the volume of speaker 6, while since cell 26 is covered, speaker 4 remains silent, or at a reduced volume. Thus, as disc 60 continues to rotate, the speakers are actuated in a continuously repeated sequence, each speaker fading out gradually as the next speaker fades in gradually, so long as the angular spacing between the center points of shoulders 122 and 124'corresponds to the angular spacing between the photocells. This provides a smooth transition of the apparent sound source from one speaker to another, but only one speaker at a time is operating at high volume.

If simultaneous high volume of two or more speakers is desired, a disc 60A such as shown in FlG. 4 may be used. Disc 60A is similar in all respects to disc 60, except that shoulders 122 and 124 thereof are spaced apart 240, rather than as in the case of disc 60. Thus, with the operation being otherwise the same as in FIG. 2, the three speakers will be at maximum volume two at a time, sequentially in the three possible combinations. Of course, any desired number of speakers may be used, with a photocell for each, and the disc configurated to provide maximum volume of any desired number of said speakers at any one time.

Disc 608, as shown in FIG. 5, is the same as disc 60 except that shoulder 122 thereof is disposed radially of the disc rather than inclined as in disc 60. Shoulder 124'is inclined as before. Thus shoulder 122 uncovers 'ach photocell comparatively rapidly, within a very small angular movement, providing a sharp attack or abrupt increase in the volume of the associated speaker. The release" of each speaker, or reduction of volume thereof, is still gradual as provided by shoulder 124. This sharp-attack, gradual-release operation provides a novel sound effect which may be desired under some circumstances. A converse gradual-attack, sharp-release effect may be obtained by inverting disc 60B, and this may be done easily by removing clamp nut 64. Disc 60C, as shown in FIG. 6, is the same as disc 608 except that shoulders 122 and 124 are spaced apart 240 rather than 120, so as to provide for operation at high volume of two speakers at any one time. This disc may also be inverted. Disc 60D, as shown in FIG. 7, is the same as disc 60 except that both of the shoulders 122 and 124 thereof are radial rather than inclined, whereby to provide both a sharp attack and a sharp release. A disc having radial shoulders spaced apart 240 could also be provided. Inversion of discs 60, 60A and 60D would have no effect.

This sequence of operation of the speakers within a single full cycle, as represented by one full revolution of the interrupter disc, may be easily changed'at will by interchanging the positions of the photocells on plate 48. This gives opportunity for still further variations of sound effect. The respective phases of each cycle of which each speaker is actuated may be varied by moving the photocells on plate 48 to different angular relationships. In this manner, for example, the transfer of volume from one speaker to another may be made to correspond to a syncopated jazz beat, which may be desired at times. Ordinarily, angular movements of the photocells on plate 48 would be made with care to insure that there would be no portion of the cycle at which none of the speakers was actuated. This might be unimportant if resistors 14 were set low enough to carry a sufficient signal to the speakers, independently of the photocells, to maintain an adequate background volume. Moreover, in such circumstances the lapse" of sound could be remedied by the provision of two parallelconnected photocells, properly balanced as to resistance, in connection with each speaker, the two photocells being spaced apart angularly on plate 48.

The principal purpose of resistors 14 is to proportion the signal reaching each speaker from source wire 8 variably between the associated resistor 14 and photocell 24, 26 or 2%. For example, said resistors may be set at a sufiiciently low value that a substantial portion of the signal reaches the speaker therethrough and is not affected by the photocell,

while only the remainder of the signal is affected and controlled by the photocell. This setting would be useful, for example, where the speakers are serving a listening area so large that no speaker by itself, even at maximum volume, could blanket it with a minimum acceptable sound intensity. Thus, a lower setting of resistors 14 could operate all of the speakers at all times with sufficient volume to provide the minimum background level, with the periodic volume increases of each provided by the photocells giving accents for sound effect purposes.

Reversing switches 32 between contacts 34 and 36 reverses the effect of the photocells. When closed on contacts36, as thus far described, an increase oflight intensity on the photocells decreases their resistance, and hence increases the volume of the speakers. When switches .32 are closed on contacts 34, the only signal path to the speakers is through resistors 14, with the photocells forming controlled parallel short circuits to ground at 38, so thatreduction of the resistance of the photocells by increase of light intensity thereon simply bleeds a greater proportion ofthe signalto ground and reduces the volume of the speakers Generally, therefore, operation with switches 32 on contacts 34 requires a lower setting of resistors 14. One effect of this reversal is that during the portion of the cycle each speaker was previously operating at maximum volume, it now is inoperative oroperating at minimum volume. Thus the effect of each of discs60A to 60D is reversed with respect to whether'it permits one or two speakers to operate 'at maximum volume at any one moment. Another effect of the reversal of switches 32 is apparent with discs 60B and 60C, in that where either. disc previously provided a sharp attach or release, it now provides a gradual attack or release, and vice versa. Thus the proper use of resistors 14 and switches 32 permits a variety of sound effects from a single interrupter disc, and the possible, combinations are greatly multiplied if the various resistors and switches are individually operated, rather than gang-operated by knobs and 42.

The sequence of operation of the speakers in each cycle of operation may be reversed many time byreversing motor76 by means of switch 90. This may be of very little importance where only two or three speakers are being used, but makes possible very dramatic sound effects when a greater number of speakers are used. For example,'when several speakers are used surrounding listening area, this reversal could cause the apparent sound source to circle the area in respectively opposite directions.

The speed or'frequency of the operational cycle provided by one revolution of the interrupter disc can "be altered at any time by moving motor 76 on plate 80 radially of shaft 54, or by adjusting resistor 88. This permits novel effects, in that a slow cycle produces a majestic, smooth and easily discernible movement of the apparent sound source, while a fast cycle produces a less discernible but wilder, more frenetic effect.

emanate principally from one speaker and intervening notes from other speakers, this may be accomplished by turning knob 116 to change the angular position of lamp switch 100 with respect to the interrupter disc.

H0. 8 shows an interrupter disc 60E which is circular, and isdivided'into three concentric annular "tracks" 128, 130 and 132. Thedisc is partially transparent and partially opaque, the opaque portions being indicated in the drawing by vertical shading. Within eachtrack, the ends of the opaque portions form shoulders 122 and 124 corresponding to those of discs 60-60DL Thus, by' slidingthe photocells 24, 26 and 28 radications of structure and operation of the apparatus itself could 3 ally on plate 48 to be disposed respectively beneath any one of tracks 128, 130 or 132, the sound pattern represented by that particular track will be caused to occur. This reduces the number of discs required to provide any desired number of sound patterns. As shown, tracks 128,. 130 and 132 provide the same patterns respectively as opaque discs 60, 60B and 60]), but this obviously is a matter of choice. A disc such as 60E could obviously be of any reasonablediameter so as to carry a greater number of tracks. in this disc, it should be noted that a disc of graduated opacity to light, such as a photographic plate of varying density, will produce substantially the same effect, as concerns gradual interruption of light, as a plate having an inclined line of demarcation between portions of complete opacity and complete transparency.

FIG. 9 shows an interrupter disc 60 1 similar to disc 6015,

having three concentric tracks 128, 130 and 132 and being;

somewhat more involved sound patterns. For example, it may; be desired to cause the apparent sound source to oscillate.

from one sideof a stage to the other. For this purpose, the speakers must be actuated in the order left, center, right; center, left, center, etc., the center speaker being actuated twice in each cycle. This operation is not possiblewith disc 60- -60D, with which each speaker can be actuated only once in each cycle of operation. FIG. 9 shows an arrangement capableof performing this pattern. It will be seen therein that tracks 128 and 132, controlling photocells 24 and 28 associated 'with left and right speakers 2. and 6, are provided with only a single pair of shoulders 122 and 124, as already described, but spaced apart only, rather than while track 130, controlling photocell26 associated with center speaker 4, is pro.

vided not only with shoulders 122 and 124, spaced apart 90,

but also with a second pair of shoulders: 122 and 124, spaced from the first pair. Thus, at the point of operation shown,

left speaker 2 is actuated and remains actuated during 90off While I have attempted to showanddescribe basic patternsand variations attainable with the apparatus shown, theactual number is virtually infinite, being limited only by the skill, ingenuity and imagination of the user. Also, many minor modifibe made without departing from the spirit of the invention.

I claim:

1. In a sound system including a plurality of loudspeakers and a source wire for delivering an operating electrical signal to each of said loudspeakers,

a. a photoelectric cell connected in series in the source wire:

of each of saidloudspeakers, said cell being of a type the electrical resistance of which varies with the intensity of light impinging thereon, b. a light source directing light toward each of said photoelectric cells, and

c. mechanically driven means for interrupting the light from.

generally planar disc disposed parallel to the plane of said cells:

and interposed'between said cells and said light source, and

means for rotatingsaid disc about its axis, said disc being off such nature as to permit passage of light to each of said cells during a predetermined portion of each revolution of said disc.

3. A system as recited in claim 2 wherein said disc is opaque to light, and has portions thereof cutaway to permit'passageof.

light therethrough.

4. A system as recited in claim 2 wherein said disc is solid, having portions thereof transparent to light and portions opaque to light.

5. A system as recited in claim 2 wherein said light source is operable to illuminate substantially the entire area of said disc, and wherein said cells are manually movable in their plane relative to a fixed support, whereby to be adjustable both radially and peripherally relative to said disc.

6. A system as recited in claim 2 wherein the lines of demarcation between light-transmitting and nontransmitting portions of said disc are disposed in different angular relationships relative to the direction of travel of said disc over each cell,. whereby the angular extent of rotation of the disc required to cover or uncover said cell is varied.

7. A system as recited in claim 1 with the addition of a manually variable resistor connected in the source wire of each loudspeaker in parallel relation with the associated photoelectric cell, whereby to proportion the flow of the electrical signal to said speaker between said resistor and said photoelectric cell.

8. A system as recited in claim 7 with the addition of a switch inserted in the source wire of each speaker between the associated photoelectric cell and the speaker, in series with said cell and in parallel with the associated resistor, said switch being operable selectively either to connect said photoelectric cell to said speaker, or to short circuit it to ground.

9. A system as recited in claim 2 with the addition of means operable to vary the speed of rotation of said disc.

10. A system as recited in claim 2 with the addition of means operable to reverse the direction of rotation of said 

1. In a sound system including a plurality of loudspeakers and a source wire for delivering an operating electrical signal to each of said loudspeakers, a. a photoelectric cell connected in series in the source wire of each of said loudspeakers, said cell being of a type the electrical resistance of which varies with the intensity of light impinging thereon, b. a light source directing light toward each of said photoelectric cells, and c. mechanically driven means for interrupting the light from said light source to said cells in a predetermined cyclical pattern.
 2. A system as recited in claim 1 wherein said photoelectric cells are mounted substantially in a plane confronting said light source, and wherein said interrupting means comprises a generally planar disc disposed parallel to the plane of said cells and interposed between said cells and said light source, and means for rotating said disc about its axis, said disc being of such nature as to permit passage of light to each of said cells during a predetermined portion of each revolution of said disc.
 3. A system as recited in claim 2 wherein said disc is opaque to light, and has portions thereof cutaway to permit passage of light therethrough.
 4. A system as recited in claim 2 wherein said disc is solid, having portions thereof transparent to light and portions opaque to light.
 5. A system as recited in claim 2 wherein said light source is operable to illuminate substantially the entire area of said disc, and wherein said cells are manually movable in their plane relative to a fixed support, whereby to be adjustable both radially and peripherally relative to said disc.
 6. A system as recited in claim 2 wherein the lines of demarcation between light-transmitting and nontransmitting portions of said disc are disposed in different angular relationships relative to the direction of travel of said disc over each cell, whereby the angular extent of rotation of the disc required to cover or uncover said cell is varied.
 7. A system as recited in claim 1 with the addition of a manually variable resistor connected in the source wire of each loudspeaker in parallel relation with the associated photoelectric cell, whereby to proportion the flow of the electrical signal to said speaker between said resistor and said photoelectric ceLl.
 8. A system as recited in claim 7 with the addition of a switch inserted in the source wire of each speaker between the associated photoelectric cell and the speaker, in series with said cell and in parallel with the associated resistor, said switch being operable selectively either to connect said photoelectric cell to said speaker, or to short circuit it to ground.
 9. A system as recited in claim 2 with the addition of means operable to vary the speed of rotation of said disc.
 10. A system as recited in claim 2 with the addition of means operable to reverse the direction of rotation of said disc.
 11. A system as recited in claim 2 with the addition of a visual signalling device, and means operable by said disc rotating means to actuate said signal once during each revolution of said disc.
 12. A system as recited in claim 11 with the addition of means operable to adjust the angular phase in a revolution of said disc at which said signal is actuated.
 13. A system as recited in claim 2 including a plurality of said discs interchangeable to provide different cyclical patterns of speaker operation. 